Lower quality cacao is often mixed into even the best chocolate, says a new research. To address this, scientists have developed a method to authenticate the purity and origin of cacao beans - the source of chocolate's main ingredient, cocoa.

Chocolate scientist Dapeng Zhang and his team found that lower-quality cacao beans often get mixed in with premium varieties on their way to becoming chocolate bars, truffles, sauces and liqueurs.

“The ability to authenticate premium and rare varieties would encourage growers to maintain cacao biodiversity rather than depend on the most abundant and easiest to grow trees," said Zhang in the research published in the Journal of Agricultural and Food Chemistry.

Applying the most recent developments in cacao genomics, they were able to identify a small set of DNA markers called SNPs (pronounced 'snips') that make up unique fingerprints of different cacao species.

The technique works on single cacao beans and can be scaled up to handle large samples quickly."To our knowledge, this is the first authentication study in cacao using molecular markers," added the researchers.Till date, researchers have found ways to verify through genetic testing the authenticity of many other crops, including cereals, fruits, olives, tea and coffee. But those methods aren't suitable for cacao beans, the study said.